`keyword-spacing` should disallow tabs (or have an option to do so)

ESLint version: 3.19.0 Problem I want to solve: accidental tabs after var and let

My proposal: Currently the keyword-spacing rule has two possible values for each sub-option: true and false. I propose adding a "space" possibility here to specify that these keywords must have a space before or after them.

Current usage, requiring an whitespace before and after every keyword

{
  "keyword-spacing": ["error", {
    "before": true,
    "after": true
  }]
}

Proposed usage, requiring any whitespace before but only spaces after it

{
  "keyword-spacing": ["error", {
    "before": true,
    "after": "space"
  }]
}

Motivation: In a style with 4-character-wide tabs, the following two lines look identical

var thing = "stuff";
var/*tab*/thing = "stuff";

The proposed tertiary option for the keyword-spacing rule would catch the second line above, preventing this common, though inconsequential, typo.

[platinumazure]

I think enhancing no-tabs to support tolerating tabs at the beginning of the line but forbidding them elsewhere makes a lot of sense.

[not-an-aardvark]

Thanks for your interest in improving ESLint. Unfortunately, it looks like this issue didn’t get consensus from the team, so I’m closing it. We define consensus as having three 👍s from team members, as well as a team member willing to champion the proposal. This is a high bar by design – we can’t realistically accept and maintain every feature request in the long term, so we only accept feature requests which are useful enough that there is consensus among the team that they’re worth adding.

Since ESLint is pluggable and can load custom rules at runtime, the lack of consensus among the ESLint team doesn’t need to be a blocker for you using this in your project, if you’d find it useful. It just means that you would need to implement the rule yourself, rather than using a bundled rule that is packaged with ESLint.